From "My Account" page: click on the Preview Thumbnail or title of the project, then click on the trash can (Delete) icon to the bottom-right of the video preview.
From the Animatron Editor: use the Main Menu (or Alt + O) to bring up the Open Project dialogue box. From here, locate the project you want to delete; hover your cursor over the project thumbnail; then, click the trash can icon in the top-right corner of the thumbnail image.
Note: before exiting the Open Project dialogue box, you are provided the option to “Restore” the project that you’ve just deleted, in case you accidentally deleted it. Once you have exited the Open Project dialogue box, you can no longer restore any deleted projects. A notification will appear at the top of your browser to confirm your deleted projects.
You can also delete the project you currently have open using the "Delete Project" option from the Main Menu.